Internal combustion engine

ABSTRACT

In an internal combustion engine having an air inlet pipe and a throttle valve rotatably mounted in the pipe on a shaft, a damper device having a housing and a yieldable wall therein which together with the housing defines a pressure chamber, a passage leading from the pressure chamber to a calibrated opening in the air inlet pipe, the opening being arranged adjacent the throttle valve such that the latter sweeps over the opening during acceleration of the engine, a drag lever operatively connected with the throttle valve, the yieldable wall and the lever being mechanically connected whereby the wall is adapted to move the lever into an end position during acceleration and during operation under load of the engine, and to release the lever from the end position at a slowed-down rate in accordance with the speed of change in air pressure determined by the size of the calibrated opening, to thereby cause a slowed-down closing of the throttle valve.

Beckmann et al.

[ INTERNAL COMBUSTION ENGINE [75] Inventors: Rudolf Beckmann; Dietrich Seelmann-Eggebert, both of Wolfsburg, Germany [73] Assignee: Volkswagenwerk Aktiengesellschaft,

Wolfsburg, Germany [22] Filed: Oct. 23, 1970 [21] Appl. No.: 83,521

[30] Foreign Application Priority Data Nov. 3, 1969 Germany 1955031 [52] US. Cl 123/103 E [51] Int. Cl F02d 11/08 [58] Field of Search 123/103 E [56] References Cited UNITED STATES PATENTS 2,005,262 6/1935 Liverance 123/103 E 2,148,729 2/1939 Coffey 123/103 E 2,575,384 11/1951 Horton.... 123/103 E 2,665,891 1/1954 Smitley 123/103 E 2,749,938 6/1956 Thomas... 123/103 E 2,782,025 2/1957 Olson 123/103 E 1 Sept. 17, 1974 Primary ExaminerWendell E. Burns Attorney, Agent, or Firm-Ernest F. Marmorek [5 7 ABSTRACT In an internal combustion engine having an air inlet pipe and a throttle valve rotatably mounted in the pipe on a shaft, a damper device having a housing and a yieldable wall therein which together with the housing defines a pressure chamber, a passage leading from the pressure chamber to a calibrated opening in the air inlet pipe, the opening being arranged adjacent the throttle valve such that the latter sweeps over the opening during acceleration of the engine, a drag lever operatively connected with the throttle valve, the yieldable wall and the lever being mechanically connected whereby the wall is adapted to move the lever into an end position during acceleration and during operation under load of the engine, and to release the lever from the end position at a slowed-down rate in accordance with the speed of change in air pressure determined by the size of the calibrated opening, to thereby cause a slowed-down closing of the throttle valve.

8 Claims, 1 Drawing Figure INTERNAL COMBUSTION ENGINE BACKGROUND OF THE INVENTION The present invention relates to internal combustion engines, and more particularly to internal combustion engines with a carburetor butterfly or throttle valve arranged on a shaft in an air intake or suction pipe or the engine and with a closing damper for influencing the throttle by means of a so-called drag lever.

As is well known in the art, the proportion of undesirable hydrocarbons in the exhaust of an internal combustion engine depends on its operation. For instance, during push operation it may be necessary to take steps to suppress or eliminate this portion of the exhaust. Under the push operation it is to be understood such an operational condition of the engine of a motor vehicle which takes place upon a sudden release of the gas pedal of the motor vehicle when the engine acts as a brake. The push operation occurs also during the downhill movement of the motor vehicle when the engine is geared on or during the shift of the gears. Customary throttle or butterfly valve adjusting means, such as described in German Printed Application DAS 1 300 339, are not quite suitable for this purpose since the engine operates in the above-mentioned push operation also when the gears are shifted, in which the device is reacting too slowly.

It is, therefore, among the principal objects of the present invention to provide an internal combustion engine of the type referred to above which will overcome this drawback.

It is another object of the invention to provide an internal combustion engine with a fast-reacting device for suppressing excessive hydrocarbons in the exhaust.

It is still another object of the invention to provide a device of the just-mentioned type which will become effective only after a certain minimum movement of the butterfly so as not to interfere with driving at very low speeds.

BRIEF SUMMARY OF THE INVENTION Whereas known closing dampers hold the throttle or butterfly valve by spring force in its position just above the idling position before the closing damper becomes effective, the present invention is characterized in that the closing damper contains a pressure chamber provided with a wall which yields to pressure variations, the pressure chamber communicating with an opening in the air inlet or suction pipe, which opening is calibrated and swept over by the butterfly valve during acceleration of the engine. Moreover, the yieldable wall is mechanically connected to the drag lever in such a way that it moves the same during operation under load and during acceleration into an end position, and releases the same from the end position during push operation in accordance with the speed of change in pressure which is determined by the size of the calibrated opening, thus assuring a slowed-down closing of the butterfly valve.

It is an important feature of the invention that the closing damper, the throttle or butterfly valve, and the calibrated opening in the suction pipe form a control circuit or system. As the butterfly valve during operation brushes or sweeps over the calibrated opening in the suction pipe which has been arranged accordingly together with this opening it forms the actual value producer. Simultaneously, however, the butterfly forms the control element in the control circuit. By calibrating the opening the speed for the closing of the butterfly can be determined.

Since the closing damper in accordance with the invention is primarily designed for quick reaction during short-time push operation, it may be advantageous to combine it with a known butterfly adjusting means. Consequently, a preferrred embodiment of the invention is characterized in that, in addition to a conduit leading to the calibrated opening, a conduit also leads from the pressure chamber to the butterfly adjusting means. This adjusting means communicates with a fur ther opening in the suction pipe, which opening is provided on that side of the butterfly which is opposite the calibrated opening.

Whereas with the just described combination the closing damper is intended to become effective very fast, the more inert butterfly adjusting means subsequently reacts for instance when one closes the butterfly at higher motor speeds. This embodiment of the invention thus represents a combination of the closing damper with a butterfly adjusting means in a single device.

A particularly compact and simple structure is ob tained by arranging the drag lever on the shaft of the butterfly and by connecting the same to the yieldable wall via a link. This link will most likely be attached at the central portion of the lever, while one end of the lever is arranged on the shaft of the butterfly and the other end rests in its end position against an adjustable abutment.

BRIEF DESCRIPTION OF THE DRAWING The invention is illustrated by way of example in the accompanying FIGURE, which is a schematic sectional view that shows a preferred embodiment of the invention wherein the damper and buterfly adjuster are combined into one device.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Referring to the drawing in detail, the device shown therein comprises a butterfly or throttle 1 which, in a manner known per se, is arranged on a shaft 2 within an air intake pipe 3. The arrow shown beneath the pipe 3 indicates the direction of the air when it is sucked into the engine. A lever 4 is likewise arranged on the shaft 2 and has its upper end fonned in such a manner that it may come to rest against an abutment 5 under a certain operating condition. In the embodiment shown the abutment is adjustable.

An important component of the invention is represented by a pressure chamber 6 which is equipped with a yieldable wall which, for example may be in the form of a diaphragm 7 that yields upon variations in pressure. It is to be understood that the yieldable wall may instead be formed by a piston. The diaphragm 7 is connected to the lever 4 by means of a link 8. In the particular embodiment shown in the drawing, a joint 9 of the link 8 with the lever 4 is located approximately in, thus near, the central portion of the lever 4.

Two conduits 10 and 11 lead into the pressure chamher 6. The conduit 10 is important for the actual damper function of the arrangement during short-term push operation of the engine of the motor vehicle. The

conduit communicates with a calibrated opening 12 in the suction pipe 3. The calibrated opening 12 is so arranged that during acceleration when the gas pedal of the motor vehicle is depressed and the shaft with butterfly valve 1 is angularly displaced in clockwise direction from its closed position (as illustrated) whereby the butterfly will sweep over the opening 12 with its left-hand edge (in the drawing). In this way, the pressure prevailing during acceleration at this point opening 12 namely the suction or underpressure will be transmitted to the pressure chamber 6 by the conduit 10 and the diaphragm 7 will move from its normal position (not shown) to the right and will pull the drag lever 4 against the abutment 5 by means of the link 8.

When changing gears, or when changing to push-' operation, the butterfly 1 will try to fall back to its closing position. However, it is prevented therefrom by the drag lever 4 which only slowly can leave its end position (shown in the drawing) and move back to its normal position as, in view of the calibration of the opening 12, the sub-atmospheric pressure is only slowly being removed in the pressure chamber 6.

By means of the further conduit 11, the pressure chamber 6 communicates with a butterfly-adjusting means 13, known per se in the art. This means 13 contains a pressure chamber 14 and a diaphragm 15. The chamber 14 is in communication with a further opening 17 in the suction pipe 3 by means of a conduit 16. The opening 17 is outside the sphere of influence of the butterfly l and on that side thereof which is opposite the calibrated opening 12. During acceleration the pressure prevailing in the range of the opening 17 is not yet sufficient to actuate the butterfly-adjusting means 13. If, however, with higher engine revolutions the butterfly 1 is suddenly caused to close, namely when changing over to push-operation, the sub-atmospheric pressure existing within the range of the opening 17 below the butterfly 1 will be transmitted by means of the conduit 16 to the chamber 14; the diaphragm will be pulled towards the left (in the drawing) and, by means of a valve 18, will establish a connection with the conduit 11 so that the sub-atmospheric pressure will also be transmitted to the chamber 6. This influence on the position of the butterfly 1 will last as long as the sum of the forces resulting from the pressure difference and surface of the diaphragm 15, as well as the force of an altitude corrector 19 is larger than the force exerted by a spring 20. Upon ventilation from the pressure chamber 6 by means of the calibrated opening 12, the valve 18 closes again. Selectively, a bore may be provided in the valve 18 or it may be omitted as is the case in the embodiment shown. The decision in favor of one or the other form may depend, among other things, upon the position of the openings 12 and 17 in the suction pipe 3.

A further advantage of the invention is found therein that the damper does not yet become effective during small opening movements of the butterfly 1. Thus, no impediment will exist during very slow driving, such as when driving in long lines of traffic. Also, in this respect the invention differs from other constructions heretofore known in which the opening of the butterfly cannot be controlled by the driver. This advantageous feature of the invention is based on the fact that the subatmospheric pressure is transmitted to the yielding wall only after the butterfly 1 has been opened to a certain extent.

We wish it to be understood that we do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

Having thus described the invention, what we claim as new and desire to be secured by Letters Patent, is as follows.

1. In an internal combustion engine having an air inlet pipe and a throttle valve rotatably mounted in said pipe on a shaft:

damper means including a housing and yieldable wall means therein which together with said housing clefines a pressure chamber, said air inlet pipe defining a calibrated opening, said calibrated opening being arranged adjacent said throttle valve such that the latter sweeps over said opening during acceleration of said engine.

means establishing a passage leading from said pressure chamber to said calibrated opening, drag lever means operatively connected to said throttle valve, and means mechanically connecting said yieldable wall means with said lever means whereby said wall means is operable to move said lever means into an end position during acceleration and during operation under load of said engine, and, respectively, to release said lever means from said end position at a slowed-down rate in accordance with the speed of change in air pressure determined by the size of said calibrated opening, thereby to cause a sloweddown closing of said throttle valve.

2. The combination of claim 1, wherein said yieldable wall means is a piston.

3. The combination of claim 1, wherein said yieldable wall means is a diaphragm.

4. The combination of claim 1, which comprises said inlet pipe having a second opening, throttle valve adjusting means, means defining a second passage connecting said pressure chamber with said throttle valve adjusting means, and means defining a third passage leading from said throttle valve adjusting means to said second opening in said air inlet pipe on that side of said throttle valve which is opposite said calibrated opening.

5. The combination of claim 1, wherein said lever means is provided on said shaft and wherein said mechanical connecting means is formed by a linkage.

6. The combination of claim 5, wherein said linkage is connected to said lever means near the center thereof, wherein one end portion of said lever means is arranged on said shaft, and adjustable abutment means operative for engagement by the other end portion of said lever means in said end position.

7. The combination of claim 4, wherein said lever means is provided on said shaft and wherein said mechanical connecting means is formed by a linkage.

8. The combination of claim 7, wherein said linkage is connected to said lever means near the center thereof, wherein one end portion of said lever means is arranged on said shaft, and adjustable abutmeans operable for engagement by the other end portion of said lever means in said end position. 

1. In an internal combustion engine having an air inlet pipe and a throttle valve rotatably mounted in said pipe on a shaft: damper means including a houSing and yieldable wall means therein which together with said housing defines a pressure chamber, said air inlet pipe defining a calibrated opening, said calibrated opening being arranged adjacent said throttle valve such that the latter sweeps over said opening during acceleration of said engine. means establishing a passage leading from said pressure chamber to said calibrated opening, drag lever means operatively connected to said throttle valve, and means mechanically connecting said yieldable wall means with said lever means whereby said wall means is operable to move said lever means into an end position during acceleration and during operation under load of said engine, and, respectively, to release said lever means from said end position at a slowed-down rate in accordance with the speed of change in air pressure determined by the size of said calibrated opening, thereby to cause a slowed-down closing of said throttle valve.
 2. The combination of claim 1, wherein said yieldable wall means is a piston.
 3. The combination of claim 1, wherein said yieldable wall means is a diaphragm.
 4. The combination of claim 1, which comprises said inlet pipe having a second opening, throttle valve adjusting means, means defining a second passage connecting said pressure chamber with said throttle valve adjusting means, and means defining a third passage leading from said throttle valve adjusting means to said second opening in said air inlet pipe on that side of said throttle valve which is opposite said calibrated opening.
 5. The combination of claim 1, wherein said lever means is provided on said shaft and wherein said mechanical connecting means is formed by a linkage.
 6. The combination of claim 5, wherein said linkage is connected to said lever means near the center thereof, wherein one end portion of said lever means is arranged on said shaft, and adjustable abutment means operative for engagement by the other end portion of said lever means in said end position.
 7. The combination of claim 4, wherein said lever means is provided on said shaft and wherein said mechanical connecting means is formed by a linkage.
 8. The combination of claim 7, wherein said linkage is connected to said lever means near the center thereof, wherein one end portion of said lever means is arranged on said shaft, and adjustable abutmeans operable for engagement by the other end portion of said lever means in said end position. 